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Old May 28th, 2017, 06:56 AM   #4341
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If MTA bothers to move the pipes, the "cut-and-cover" method is still a cheaper and better way to build subway. MTA should stop building station cavern unless they meet bedrock. A less costly alternative is building underground tubes like those in London but the "cut-and-cover" method is more suitable for New York City.
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Old May 28th, 2017, 10:37 AM   #4342
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Existing underground infrastructure isn't the problem; aboveground traffic and neighbourhood resistance are.
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Old May 28th, 2017, 04:03 PM   #4343
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Quote:
Originally Posted by mrsmartman View Post
If MTA bothers to move the pipes, the "cut-and-cover" method is still a cheaper and better way to build subway. MTA should stop building station cavern unless they meet bedrock. A less costly alternative is building underground tubes like those in London but the "cut-and-cover" method is more suitable for New York City.
and..

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Originally Posted by Alargule View Post
Existing underground infrastructure isn't the problem; aboveground traffic and neighbourhood resistance are.
Excellent points.. and the bottom line is that the cut and cover method will not be used to build any subways in NYC. Just my opinion.
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Old May 28th, 2017, 06:09 PM   #4344
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Not just a problem in NYC, btw; this is what motivated the choice to construct Amsterdam's newest underground line by tbm's rather than the caisson method used to construct the first line in the 70's.
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Old May 28th, 2017, 07:11 PM   #4345
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Express tracks cannot be built without the tried-and-true "cut-and-cover" method, which is more suitable for New York City.
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Old May 28th, 2017, 08:24 PM   #4346
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Nonsense. Just bore four tunnels instead of two. Using tbm's will even allow for more flexibility in track layout: four tracks at the same level or two-by-two below each other, or a combination thereof. There's no reason a four track line couldn't be built by other means than cut n cover.
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Old May 28th, 2017, 09:43 PM   #4347
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TBM= Tunnel boring method is rather expensive in NYC. Why? Construction cost are out out site and...;

Quote:
New York City is the site of ancient earth-shaking and earth-shaping events.*(see diagrams below.) The bedrock that anchors the city’s skyscrapers tells a story of a place going back more than a billion years. The island of Manhattan is built on three strata known as Manhattan Schist, Inwood Marble, and Fordham Gneiss. Schist forms the island’s spine from the Henry Hudson Bridge on its north end to the Battery on its southern tip; it dips abruptly several hundred feet below ground at Washington Square, and makes a gradual ascent beginning at Chambers Street. These dips and rises account for the gap between “midtown” and “downtown” in the Manhattan skyline, since tall buildings had to be anchored on solid bedrock, and not on the glacial till that fills the valleys. The contemporaneous Inwood Marble, metamorphosed from limestone, forms beds 150 to 500 feet thick beneath the Harlem River and adjacent regions known to geologists as Inwood Lowland; it underlies the East River and the Harlem Lowland and above ground forms a ridge from Dyckman Street on the upper west side northward to Marble Hill. The billion-year-old Fordham Gneiss erupts to the surface in the Bronx, forming the Riverdale and Grand Concourse ridges. The three strata are complexly interfolded. Each layer tells its own geological story from which we can reconstruct the geological map of New York City.
http://www.newyorknature.net/Geology.html
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Old May 29th, 2017, 03:30 AM   #4348
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Quote:
Originally Posted by bd popeye View Post
TBM= Tunnel boring method is rather expensive in NYC. Why? Construction cost are out out site and...;

http://www.newyorknature.net/Geology.html
Many cities around the world tunnel through (and build upon) schist. To be certain, it isn't the method of boring the tunnels that's expensive (an in-depth examination of the actual tunneling costs of recent projects - ESA*, SAS, 7 Ext.* - would probably show them to be fairly in-line with similar projects, internationally): It's the deep, cavernous stations that are one of the biggest culprits.

Also, the urban legend about downtown and midtown being distinct because of geology is just a myth; it has everything to do with zoning and the emergence of transit hubs in key areas of the city.

* these two seem to have much of the work associated with stations/finishes bundled together with excavation ¯\_(ツ)_/¯
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Old May 29th, 2017, 04:44 AM   #4349
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Originally Posted by phoenixboi08 View Post
Many cities around the world tunnel through (and build upon) schist. To be certain, it isn't the method of boring the tunnels that's expensive (an in-depth examination of the actual tunneling costs of recent projects - ESA*, SAS, 7 Ext.* - would probably show them to be fairly in-line with similar projects, internationally): It's the deep, cavernous stations that are one of the biggest culprits.

Also, the urban legend about downtown and midtown being distinct because of geology is just a myth; it has everything to do with zoning and the emergence of transit hubs in key areas of the city.

* these two seem to have much of the work associated with stations/finishes bundled together with excavation ¯\_(ツ)_/¯
They could perhaps do something like the Barcelona Metro line 9/10, which has two tracks (and platforms!) in a single large tunnel. That way, they can just do a single drive from 55th St all the way down to Houston, maybe even start Phase 4 so the same mega TBM can be used to drive all the way down to Whitehall St or even Brooklyn.

I believe big, cavernous stations would only make sense where the stations are built by cut and cover, to reduce the amount of backfill one might need. But yeah, for the mined stations, maybe a more Crossrail-like design might be more economical, but then again that might drive up design costs.
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Old May 29th, 2017, 08:59 AM   #4350
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About the fantasy SAS plan: I like the idea behind it to better integrate the SAS into the existing network. I've always wondered why the SAS was so badly integrated into the rest of the network, with almost no logical transfers to lines it crosses. As I infer from the article, the main reason for that is that the SAS was conceived of as solving a local traffic problem (overburdening of the Lexington Ave line in Manhattan).

However, integrating it the way it has been proposed in the fantasy plan will probably be prohibitively expensive. A more realistic approach might be to extend the planned SAS on both ends: to the north to the Bronx (instead of the proposed terminal station at 125 St), eventually connecting to the Pelham line to ease congestion on the 6 (tunnel structures would have to be widened and platforms narrowed to allow the wider B division stock to fit in), which would then terminate at 3 Av-138 St to allow for easy transfer between the Pelham line and the 6.

To the south, the line could be extended via a new tunnel under the East River to a connection with the Court St stub, thus alleviating congestion on the Cranberry St tubes (A/C) and allowing for more frequent service along the Fulton St line. A/C trains would serve the express tracks; T trains would run via the local tracks.
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Old May 29th, 2017, 09:32 AM   #4351
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Quote:
Originally Posted by Alargule View Post
About the fantasy SAS plan: I like the idea behind it to better integrate the SAS into the existing network. I've always wondered why the SAS was so badly integrated into the rest of the network, with almost no logical transfers to lines it crosses. As I infer from the article, the main reason for that is that the SAS was conceived of as solving a local traffic problem (overburdening of the Lexington Ave line in Manhattan).

However, integrating it the way it has been proposed in the fantasy plan will probably be prohibitively expensive. A more realistic approach might be to extend the planned SAS on both ends: to the north to the Bronx (instead of the proposed terminal station at 125 St), eventually connecting to the Pelham line to ease congestion on the 6 (tunnel structures would have to be widened and platforms narrowed to allow the wider B division stock to fit in), which would then terminate at 3 Av-138 St to allow for easy transfer between the Pelham line and the 6.

To the south, the line could be extended via a new tunnel under the East River to a connection with the Court St stub, thus alleviating congestion on the Cranberry St tubes (A/C) and allowing for more frequent service along the Fulton St line. A/C trains would serve the express tracks; T trains would run via the local tracks.
I personally would offset slightly the planned 125 St station towards the east, so that it spans between Third and Lexington Avenues like Lex/53 and Lex/63. That way, the turn towards the Bronx can happen under the IRT station instead.

Also, the way he had the 125th St Crosstown, I would rather the tracks turn under the existing 125/8Av station, then feeding into the unused layup tracks in the 135th St area. This could allow for some kind of off-peak service through to 168th St via CPW, and/or SAS trains to be put in from 207th yard. It would potentially be quite a sharp turn like how 75-footers can't be used on the Jamaica Line, but I guess by then NYCT would have a 60-footer only fleet so it won't be that much of an issue.

His proposal of making the Nassau St line a shuttle and giving the Manhattan Bridge to 2nd Ave doesn't really click well with me, more like reshuffling services for the sake of it instead of providing any real transport benefit. If a connection with the BMT is desired, perhaps the new SAS Brooklyn tunnel could also have a link to either the Culver or 4th Avenue lines, with access to the rest of the BMT via Coney Island Yard, if the connection to the 8th Avenue line isn't enough.

The real benefit of provisions for a 4-track line on 2nd Ave would only be realized if the Third Ave line in the Bronx was built, besides all these plans. Also, I propose a swap in the Houston St area - connect the local tracks of 2Av to the Nassau St line, and the express to the Manhattan Bridge. The 3rd Ave service would run local to Broad St, while Brooklyn-bound trains (from Queens or the 125th St Crosstown) run express, stopping only at 116, 72, 42 and Houston Streets.
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Old May 29th, 2017, 04:12 PM   #4352
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Quote:
Originally Posted by bd popeye View Post
and..



Excellent points.. and the bottom line is that the cut and cover method will not be used to build any subways in NYC. Just my opinion.
The "cut-and-cover" subway is a reasonable solution to replace the original elevated viaduct.
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Old May 29th, 2017, 04:30 PM   #4353
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No, because traffic and neighborhood resistance. Furthermore, I'd believe excavating even a two-track subway would today be even more expensive than boring two tubes. That has to do with the additional cost of excavating more earth, rock and rubble if you have to dig the tunnel from the surface down. Of course, part of what you excavate could be re-used to fill up the space above the tunnel once dug out, but all that time you'd have to leave that material somewhere.

Given the great advancements in tunnel boring techniques, constructing a tunnel by tbm's might well be cheaper by the mile than a more conventional cut-and-cover method would be today. Maybe if you'd just construct a 'subway' in the real sense of the word - a tunnel running directly beneath the street surface - like has been done with the early subways, cut and cover could be cheaper. But that would meet with other disadvantages: no mezzanines, requiring side platforms accessible only from one side of the street; more noise because the trains run just below the surface; and the necessary relocation of all kinds of tubes and pipes running directly below street level.
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Old May 30th, 2017, 06:35 AM   #4354
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Quote:
Originally Posted by Alargule View Post
No, because traffic and neighborhood resistance. Furthermore, I'd believe excavating even a two-track subway would today be even more expensive than boring two tubes. That has to do with the additional cost of excavating more earth, rock and rubble if you have to dig the tunnel from the surface down. Of course, part of what you excavate could be re-used to fill up the space above the tunnel once dug out, but all that time you'd have to leave that material somewhere.

Given the great advancements in tunnel boring techniques, constructing a tunnel by tbm's might well be cheaper by the mile than a more conventional cut-and-cover method would be today. Maybe if you'd just construct a 'subway' in the real sense of the word - a tunnel running directly beneath the street surface - like has been done with the early subways, cut and cover could be cheaper. But that would meet with other disadvantages: no mezzanines, requiring side platforms accessible only from one side of the street; more noise because the trains run just below the surface; and the necessary relocation of all kinds of tubes and pipes running directly below street level.
The main capital costs of the The SAS was the Cavern stations, if they built stations similar to York St, High St, or Fulton St. the Station costs would be less than what they were.
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Old May 30th, 2017, 08:30 AM   #4355
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Stations could be excavated from the surface down by using cut and cover techniques; the tunnels in between could be bored. There are many places in the world (Amsterdam, Paris, Moscow) where new metro lines are built just like that. However, it would still mean a large part of the street would have to be torn up, and that again means major traffic disruption and a good chance of neighborhood opposition. Averting those might be a good reason to politically justify the extra costs of building stations the way they've been built for the SAS (and the 7th Avenue extension and ESA, for that matter).
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Old May 30th, 2017, 05:44 PM   #4356
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Vintage train of R9s, D-Types, & BU Gate Cars being moved to 207th Street yard all in ONE train:
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Old May 30th, 2017, 06:23 PM   #4357
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I think it is great that the vintage rolling stock is preserved, maintained & operated from time to time.

@ Alargule...You more than likely know but the recently opened second AV subway cost $4.5..billion dollars.

http://gothamist.com/2016/12/29/2nd_...er.php#photo-1

I wonder how much the second and third phases will cost?
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Old May 30th, 2017, 06:48 PM   #4358
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Quote:
Originally Posted by Arnorian View Post
Full system track map with proposed changes to 2nd Av Subway plan.

http://www.vanshnookenraggen.com/_in...avenue-subway/
The biggest problem with this plan is that it demands various changes that aren't necessary at this phase (lets assume this phase includes the 125th Crosstown), and often aren't even related to the main point of provision for SAS expansion to 4-tracks. These detract from that main point, as can be seen by the comments under the article that are mostly not about the 2nd Av subway, but the other changes (that were more of the article).

The SAS's biggest problem has always been the dependency on tentacles everywhere and wide-reaching changes in the outer boroughs (including new lines). Until the recent moves to take a KISS approach and actually get something built, it was always came with a big bunch of baggage - rerouted trains, a reliance on various branches being built all across the city, etc and so it was hard to get built as (with a couple of exceptions) you couldn't build small sections and phase the line. This article falls into the crayon playing about that scuppered the SAS in the 30s, 40s, 50s, 60s, 70s...

And, even if you took out the massive reworking of the Jamaica line and Atlantic Avenue locals that aren't even related to the SAS, there's still the Rockaway-Rego Park subway that isn't actually essential to the 4-track provision, but its inclusion in the article makes it seem so.

Now these inessential / unrelated changes might be useful, but they detract from, and drown out, the point trying to be made, undermining it and dumping a load of baggage onto it.
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Old May 30th, 2017, 07:42 PM   #4359
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Agreed.

The main complaint behind why that plan was designed the way it was seems to be "SAS has few connections to other parts of the system".

While it does have merit, it's actually not as bad as one thinks.

As designed, the full SAS already has connections to the 6 Av, Broadway, and Queens Boulevard lines, of which the former two provide access to most of the BMT, and 6 Av/QBL give access to the large majority of the IND via West 4 St or the QBL itself.

To best unlock the potential of the SAS as a trunk line, only two sections of line would need to be built:
  1. Connecting the SAS via a 125th Crosstown to the CPW line
  2. the Brooklyn tunnel to Court St, with a connection to the Culver line

The first connection would allow A B C D trains from Inwood or the Bronx to reroute via 2nd Ave and the 63rd St tunnel should there be an issue on Central Park West, and provide access to the 207th St Yard.

The second connection would also give A C F trains a way around the lines feeding into Jay St-Metrotech should there be something in that area. A C trains would have to join from 145th St, while F trains join from the 63rd St Tunnel. This would also provide the SAS direct access to Coney Island Yard and terminal.
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Old May 30th, 2017, 08:03 PM   #4360
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Double-track Second Avenue Subway would limit the amount of possible connections to other subway lines.
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